1. Technical Field of the Invention
The present invention relates in general to a communication system and in particular to a wireless communication system. More particularly, the present invention relates to a communication system with more than one type of radio access.
2. Description of the Related Art
In the mobile Internet world, users may have more than one type of radio access available to connect to an application server. Radio accesses (access bearers) to applications on the Internet that may be available to a user include: Short Message Service (SMS), Unstructured Supplemental Service Data (USSD), Circuit Switched Data (CSD), General Bluetooth™ Packet Radio Services (GPRS), Universal Mobile Telephone System (UMTS) and Bluetooth™ (a short range, high frequency communication protocol). Each of these access bearers has different attributes or capabilities including transmission speed (bandwidth).
Wireless Application Protocol (WAP) is a technology that enables wireless access to Internet applications from a wireless terminal (cell phone, wireless modem, etc.) The WAP Forum, a nonprofit organization formed for administering the WAP Specification process, has defined a WAP architecture for pulling information from the Internet (Internet browsing) and pushing (application initiated) information (sending news messages, mail notification, etc.) to a user.
The WAP Forum, in its Wireless Application Environment (WAE), has adopted an application framework for access to the Internet by wireless terminals such as mobile phones, pagers and Personal Digital Assistants (PDAs). This specification closely follows the World Wide Web (WWW) model. All content is specified in formats that are similar to standard Internet formats. Content may be transported using standard protocols in the WWW domain and an optimized HTTP-like protocol in the wireless domain such as the Wireless Session Protocol (WSP), a WAP communication protocol.
A mobile phone may initiate a data call in the GSM network, in a packet switched data network like the General Packet Radio Services (GPRS), or the Universal Mobile Telephone System (UMTS) which is the standard for the next generation mobile telephone system in Europe. There is also the possibility to use short-range radio access technology like Bluetooth™.
FIG. 1 illustrates a communication system in which a wireless terminal may establish connection to an application server via a WAP Gateway and an IP network utilizing one of many access bearers (e.g. Bluetooth™, GSM, GPRS or UMTS). Mobile phone 102 can connect to an Application Server 114 using Wireless Application Protocol (WAP) Gateway 114 via one of several types of access technology.
In FIG. 1, Application Server 116 is connected to WAP Gateway 114 via a LAN (not shown) or via an Internet Protocol (IP) network (not shown) and WAP Gateway 114 may in turn be connected to mobile phone 102 via IP network 112. The protocol used by WAP Gateway 114 to reach applications residing in Application Server 116 may be accomplished by using Hypertext Transfer Protocol (HTTP), a well-known and established standard protocol for transporting hypertext documents around the Internet.
Application Server 116 is not aware of the bearer type by which the mobile phone 102 gained access. However, if the bearer type that is used is not according to preferred access means, there could be reduced capability of the connection. For example, if mobile phone 102 was connected using an SMS bearer connection and a WAP page is selected that was designed for CSD (9.6 Kbps), the downloading time for the page may be too long and inconvenient for the end user.
FIG. 2 depicts a high-level block diagram of a GSM and UMTS network with typical coverage for radio accesses in a mobile network. In a Public Land Mobile Network (PLMN) different access types co-exist and will typically be unevenly deployed in the network at any given time. An operator that has GSM coverage and is in the process of introducing GPRS will start introducing GPRS in selected areas first, such as cities. The same procedure will likely be followed when introducing a next generation mobile system, e.g., UMTS. The reason for gradually introducing access bearers into a PLMN that have higher capacity is generally related to cost because of the necessary investment in infrastructure
Mobile phones may move around in the PLMN area and, depending on the radio access availability, be able to use different access bearers (for simplicity, only Bluetooth™ is illustrated here). Another aspect regarding the choice of bearer, except for different downloading times, is related to the different costs for using different bearers, i.e., it may be cheaper to implement one access bearer before another bearer.
A drawback with communication systems used today is that the information about the bearer may not be known to the application, for example, when using WAP. One object of the present invention is to increase and optimize a user's accessibility of application information, including reducing download time for the user. Another object of the present invention is to provide a communication system that identifies the access bearer capability to the application.